How to launch chefrun on provisioned vm.

If launch chefrun after provisionVms, its complete with success result.
If create workflow for update exists vms, step not run chef.

```
workflow("update") {
  steps {
    chefrun {
      phase = "install"
      roles = ['exampleNode']
      runList = ["recipe[nginx]"]
    }
  }
}
```

How to configure step for update vm?
